1. Field of the Invention
The present invention refers to an elastic safety valve for escape of fluids, which has been specially designed so that it opens when the differential pressure reaches a determined threshold value, allowing the fluid causing this pressure to escape, and closes hermetically when the differential pressure drops below the opening threshold.
2. The Prior Art
Safety valves and pressure-relief valves are known and constitute complex, generally bulky mechanisms for various applications. Also, valves for releasing excess pressure in contact lens containers are known. When hydrogen peroxide is used for disinfecting contact lenses, excess pressure is created. Some of the known valves consist of a small capillary in the wall of the lid that permits gasses to escape, reducing excess pressure. Due to the small caliber of the opening, liquid cannot spill out. The surface tension of the liquid is sufficient to close the capillary opening. However, liquid can escape if the container is shaken. Small increases in pressure produced by a rise in the temperature of the container when carried in a pocket, as is frequently done, may produce small bothersome spills. Moreover, an obstruction of the capillary orifice may cause the container to explode if the contact lenses are disinfected with a 10% solution by volume of hydrogen peroxide.
Other valves have an orifice filled with a water-proof fibrous material. This material forms a dense filter that allows gas to escape but prevents the passage of liquids. Liquids, especially aqueous solutions, create a surface tension due to the water-proof nature of the fibers. These valves, though they initially work well, are fairly sensitive to obstructions and are relatively expensive to make.
Moreover, valves which distribute fluids through branched duct systems are known. These valves are used for machine lubrication or drip-irrigation systems. They consist of strangulation nozzles on the ends of ducts, which are made of rigid material and have a fixed outlet aperture. These valves have the same disadvantage of being easily obstructed by solid residue which may cause a dangerous increase in pressure in the corresponding duct.